1. Field of the Invention
The present invention relates to an adhesive strength increasing method for a metal thin film, and in particular to an improved adhesive strength increasing method for a metal thin film which is capable of significantly enhancing an adhesive strength between a metal thin film and a substrate formed of silicon or glass.
2. Description of the Conventional Art
Recently, as the high-tech technology advances, a light-thin-compact product is desperately needed. In particular, in the optical and electronic industry field, the method for increasing an adhesive strength between a metal thin film and a glass substrate is considered as the most important method.
As the methods for increasing an adhesive strength between the metal thin film and the glass substrate, there are known a method for washing the glass substrate in an ultrasonic container by using acetone, methanol, ethanol, etc., rewashing the same by using distilled water, and dehydrating the same in an oven having a filter for more than one hour at about 200.degree. C. for preventing dust from being introduced thereinto, and a method for washing and dehydrating in the same manner as in the previous method and depositing Cr, Ti, etc., which has a good adhesive strength with respect to the glass substrate, on the glass substrate and then depositing a metal on the resultant material.
However, the earlier method has a slightly increased adhesive strength but does not have a substantial adhesive strength under environment in which there are much friction and abrasion, and the later method has an advantage in that the adhesive strength is greatly increased but has a disadvantage in that since an additional metal such as Cr, Ti, etc., is used as a buffer layer, the metal of the buffer layer is spread out onto the metal layer formed on the buffer layer, thus forming a new phase, whereby the characteristic of the material may be degraded.
In addition, there is an ion beam mixing method which is directed to forcibly mixing at a boundary formed between a substrate and a thin film. Since the method needs a high ion energy, a bulky apparatus such as an ion implanter or a Van der Graaf accelerator is required, so that it is difficult to actually use the above-described method. In particular, it is impossible to increase an adhesive strength with respect to Au and glass material by using this method.